//gis根据一个点的经纬度、方位角、半径求下个点的经纬度 再画线
var poine2=getLonAndLat(data[0].lng,data[0].lat,data[0].azimuth,data[0].radius);
var polyline = new BMap.Polyline([
new BMap.Point(data[0].lng,data[0].lat),//起始点的经纬度
new BMap.Point(poine2.lng,poine2.lat)//终止点的经纬度
], {strokeColor:“blue”,//设置颜色
strokeWeight:2, //宽度
strokeOpacity:0.7});//透明度
map.addOverlay(polyline);
var circle = new BMap.Circle(point2,data[0].radius,{strokeColor:"blue", strokeWeight:2, strokeOpacity:0.5});
map.addOverlay(circle);
下面是经纬度获取脚本
/**
- 度换成弧度
- @param {Float} d 度
- @return {[Float} 弧度
/
function rad (d){
return d * Math.PI / 180.0;
};
/* - 弧度换成度
- @param {Float} x 弧度
- @return {Float} 度
/
function deg (x){
return x180/Math.PI;
};
/** - @param {*} lng 经度 113.3960698
- @param {*} lat 纬度 22.941386
- @param {*} brng 方位角 45 ---- 正北方:000°或360° 正东方:090° 正南方:180° 正西方:270°
- @param {*} dist 距离 9000
*/
function getLonAndLat (lng,lat,brng,dist){
//大地坐标系资料WGS-84 长半径a=6378137 短半径b=6356752.3142 扁率f=1/298.2572236
var a=6378137;
var b=6356752.3142;
var f=1/298.257223563;
var lon1 = lng*1;
var lat1 = lat*1;
var s = dist;
var alpha1 = rad(brng);
var sinAlpha1 = Math.sin(alpha1);
var cosAlpha1 = Math.cos(alpha1);
var tanU1 = (1-f) * Math.tan(rad(lat1));
var cosU1 = 1 / Math.sqrt((1 + tanU1*tanU1)), sinU1 = tanU1*cosU1;
var sigma1 = Math.atan2(tanU1, cosAlpha1);
var sinAlpha = cosU1 * sinAlpha1;
var cosSqAlpha = 1 - sinAlpha*sinAlpha;
var uSq = cosSqAlpha * (a*a - b*b) / (b*b);
var A = 1 + uSq/16384*(4096+uSq*(-768+uSq*(320-175*uSq)));
var B = uSq/1024 * (256+uSq*(-128+uSq*(74-47*uSq)));
var sigma = s / (b*A), sigmaP = 2*Math.PI;
while (Math.abs(sigma-sigmaP) > 1e-12) {
var cos2SigmaM = Math.cos(2*sigma1 + sigma);
var sinSigma = Math.sin(sigma);
var cosSigma = Math.cos(sigma);
var deltaSigma = B*sinSigma*(cos2SigmaM+B/4*(cosSigma*(-1+2*cos2SigmaM*cos2SigmaM)-
B/6*cos2SigmaM*(-3+4*sinSigma*sinSigma)*(-3+4*cos2SigmaM*cos2SigmaM)));
sigmaP = sigma;
sigma = s / (b*A) + deltaSigma;
}
var tmp = sinU1*sinSigma - cosU1*cosSigma*cosAlpha1;
var lat2 = Math.atan2(sinU1*cosSigma + cosU1*sinSigma*cosAlpha1,
(1-f)*Math.sqrt(sinAlpha*sinAlpha + tmp*tmp));
var lambda = Math.atan2(sinSigma*sinAlpha1, cosU1*cosSigma - sinU1*sinSigma*cosAlpha1);
var C = f/16*cosSqAlpha*(4+f*(4-3*cosSqAlpha));
var L = lambda - (1-C) * f * sinAlpha *
(sigma + C*sinSigma*(cos2SigmaM+C*cosSigma*(-1+2*cos2SigmaM*cos2SigmaM)));
var revAz = Math.atan2(sinAlpha, -tmp); // final bearing
var lngLatObj = {lng:lon1+deg(L),lat:deg(lat2)}
return lngLatObj;
}
/**
- 度换成弧度
- @param {Float} d 度
- @return {[Float} 弧度
/
function rad (d){
return d * Math.PI / 180.0;
};
/* - 弧度换成度
- @param {Float} x 弧度
- @return {Float} 度
/
function deg (x){
return x180/Math.PI;
};
/** - @param {*} lng 经度 113.3960698
- @param {*} lat 纬度 22.941386
- @param {*} brng 方位角 45 ---- 正北方:000°或360° 正东方:090° 正南方:180° 正西方:270°
- @param {*} dist 距离 9000
*/
function getLonAndLat (lng,lat,brng,dist){
//大地坐标系资料WGS-84 长半径a=6378137 短半径b=6356752.3142 扁率f=1/298.2572236
var a=6378137;
var b=6356752.3142;
var f=1/298.257223563;
var lon1 = lng*1;
var lat1 = lat*1;
var s = dist;
var alpha1 = rad(brng);
var sinAlpha1 = Math.sin(alpha1);
var cosAlpha1 = Math.cos(alpha1);
var tanU1 = (1-f) * Math.tan(rad(lat1));
var cosU1 = 1 / Math.sqrt((1 + tanU1*tanU1)), sinU1 = tanU1*cosU1;
var sigma1 = Math.atan2(tanU1, cosAlpha1);
var sinAlpha = cosU1 * sinAlpha1;
var cosSqAlpha = 1 - sinAlpha*sinAlpha;
var uSq = cosSqAlpha * (a*a - b*b) / (b*b);
var A = 1 + uSq/16384*(4096+uSq*(-768+uSq*(320-175*uSq)));
var B = uSq/1024 * (256+uSq*(-128+uSq*(74-47*uSq)));
var sigma = s / (b*A), sigmaP = 2*Math.PI;
while (Math.abs(sigma-sigmaP) > 1e-12) {
var cos2SigmaM = Math.cos(2*sigma1 + sigma);
var sinSigma = Math.sin(sigma);
var cosSigma = Math.cos(sigma);
var deltaSigma = B*sinSigma*(cos2SigmaM+B/4*(cosSigma*(-1+2*cos2SigmaM*cos2SigmaM)-
B/6*cos2SigmaM*(-3+4*sinSigma*sinSigma)*(-3+4*cos2SigmaM*cos2SigmaM)));
sigmaP = sigma;
sigma = s / (b*A) + deltaSigma;
}
var tmp = sinU1*sinSigma - cosU1*cosSigma*cosAlpha1;
var lat2 = Math.atan2(sinU1*cosSigma + cosU1*sinSigma*cosAlpha1,
(1-f)*Math.sqrt(sinAlpha*sinAlpha + tmp*tmp));
var lambda = Math.atan2(sinSigma*sinAlpha1, cosU1*cosSigma - sinU1*sinSigma*cosAlpha1);
var C = f/16*cosSqAlpha*(4+f*(4-3*cosSqAlpha));
var L = lambda - (1-C) * f * sinAlpha *
(sigma + C*sinSigma*(cos2SigmaM+C*cosSigma*(-1+2*cos2SigmaM*cos2SigmaM)));
var revAz = Math.atan2(sinAlpha, -tmp); // final bearing
var lngLatObj = {lng:lon1+deg(L),lat:deg(lat2)}
return lngLatObj;
}
效果图:
这篇博客介绍了一种使用JavaScript根据给定的经纬度、方位角和半径来计算下一个点的经纬度的方法,并用这些点创建线和圆。通过调用getLonAndLat函数并传入相应的参数,可以实现GIS坐标转换,然后利用BMap库绘制地图元素。
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